The Research On The Three-dimensional Seismic Isolation Pier Finite Element And Vibration Isolation Performance

Isolation technology is a time-honored technology.The base isolation technology which sprung up in 1960s has experienced a large number of studies,tests and engineering practice,particularly tests of strong earthquakes,which demonstrates that it is an effective way to decrease seismic loss for architectural structures.Compared with traditional anti-seismic technologies,isolation technology possesses obvious advantages,with huge application prospect,so it has developed rapidly in recent years.The earthquake is a type of extreme natural disaster which often occurs suddenly.It can cause enormous damages to the society,such as property damage and loss of life.It is generally acknowledged that only horizontal direction seismic vibration effects are taken into consideration.Existing national Norms of Anti-seismic Design of Buildings and base isolation technology mainly focus on isolating horizontal vibration,namely vertical seismic effects will be considered only in 8 to 9 stories high buildings and long-span structures.What cannot be neglected is that effects of seismic wave are complicated.In high intensity areas and near the epicentral areas,vertical seismic effects are apparent,whose destructive effects on architectural structures cannot be neglected.Studies on seismic isolation technologies which isolate vertical and horizontal seismic effects at the same time has been relatively deficient.This paper puts forward a new type base isolation bearing—three-dimensional seismic isolation pier which considers not only horizontal seismic load,but also vertical seismic effects.This three-dimensional device is composed by an upper pier,a lower pier,a side pier,a isolation spring and pitch factice.This bearing,with simple structure and low price,is fit for being popularizing in villages and small towns in China.This paper introduces the design theory,working principles,construction features and workmanship of this three-dimensional seismic isolation pier.In this paper,the quasi-static load test of the test-piece of the three-dimensional device is conducted.It obtains vertical bearing capacity,horizontal stiffness and vertical stiffness of the pier and makes comparative analysis with designed theoretical values.On this basis,ANSYS is utilized to set up a four-tier frame structural isolation and non-seismic isolation models which are used to make time-history analysis,and study on the isolation performance of the three-dimensional device.The results of quasi-static load test show that test results and designed theoretical values are identical,which verifies the reasonability of the design theory.The results of finite element analysis indicate that when coupled vertical seismic vibrations are taken into consideration,if section internal force of some beams and piers increase,the vertical seismic effects in isolation designs cannot be ignored and isolation piers are featured with favorable isolation effects.